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[Q] Help with AT&T bands, or why the rest of the world is more advanced than the U.S.

[Q] Help with AT&T bands, or why the rest of the world is more advanced than the U.S.
I need to buy a smartphone before the end of June for use in my new life in mainland China, but have ended up with many questions regarding how useful my phone would be if I returned to the U.S.
So China, being civilized like the rest of the world, uses only the 2100 band GSM for its 3G, at least at China Unicom. So as far as I understand, any phone that gets GSM 2100 gets 3G.
The trouble is what happens if I move back to the U.S.? I want a phone that will last for years. Seems like the only game in town is AT&T unless the feds stop the T-Mobile deal. So my phone has to be 850/1900/2100 to get 3G in the U.S., as I understand it. (At&T isn't exactly forthcoming on this on its site, so this is from this forum and other sources.)
My two candidates are the LG Optimus 2X and the Samsung Nexus S. The 2X has 900/1900/2100 3G bands and decent enough hardware that I'm relatively futureproof gear-wise. The Nexus S has -- at least where I live currently -- 900, 1700 and 2100 3G bands, and Google's stamp of approval means I'm futureproof on the software side.
My confusion comes from what all these numbers mean. Does my phone has to be just one of these bands to get 3G? Two of them? Or is all this a misnomer, and 1900/2100 is in fact its own unique band? Why do I need all these extra bands when most countries have just 2100? What am I missing if I go LG 2X and miss the 850 band?
Does having only two and not all three on my phone mean I would get 3G data only some of the time? Or must I meet all these criteria? Is one upload and one download?
And why is U.S. telecom so screwed up while the rest of the world seems to do just fine? (OK that one may be more of a rant than a question)
There are phones that hit on all the bands, but Motorola is closed software-wise and I don't want that, while Samsung Galaxy S II and iPhone 4 are both too expensive for me.
I'm clearly slow, and not an expert, but if anyone has time to educate me I would much appreciate it.

Hmm, this site suggests AT&T works on either 850 OR 1900. In other words, you need just one or the other on your phone, but not both:
wwwSPACE.cellularmaps.com/att_850_1900.shtml ((sorry I still can't link))
So the LG Optimus 2X would work in U.S.? Pity about Nexus S, because I prefer it for the likely long-term developer support, but life wouldn't be so bad with the Optimus 2X, now would it?

So I have no idea whether this is true, but Google and message boards tell me AT&T has two 3G bands, one 850 and one 1900. They don't need each other to work. Instead, they just duplicate.
Why? I don't know. There may be no logical reason, this being AT&T.
So that suggests in places where AT&T has kept 1900, a phone like the LG Optimus 2X (900/1900/2100) will work fine, and in places where it doesn't it won't. This map suggests wide overlap.
(Still can't post links. Great. Google "cellular maps" "AT&T" "850" and "1900." Thank God the board is safe from links!)
Bear in mind that none of what I've written here fits the definition of "fact." I have no education in this. But somebody's gotta continue the conversation and I'm unafraid to look stupid.

Norlos said:
So I have no idea whether this is true, but Google and message boards tell me AT&T has two 3G bands, one 850 and one 1900. They don't need each other to work. Instead, they just duplicate.
Why? I don't know. There may be no logical reason, this being AT&T.
So that suggests in places where AT&T has kept 1900, a phone like the LG Optimus 2X (900/1900/2100) will work fine, and in places where it doesn't it won't. This map suggests wide overlap.
(Still can't post links. Great. Google "cellular maps" "AT&T" "850" and "1900." Thank God the board is safe from links!)
Bear in mind that none of what I've written here fits the definition of "fact." I have no education in this. But somebody's gotta continue the conversation and I'm unafraid to look stupid.
Click to expand...
Click to collapse
The bands are frequency ranges, so it means that the phone will broadcast/receive on the 850 MHZ range, or 1900 MHZ range. Don't know if this helps, but that is what they are talking about.

Check out PDADB
I think you will find www.pdadb.net to be your new friend. So bottom line is if you want AT&T 3G you need 850/1900, Australia and Canada are the only other places that utilize these bands for their 3G from my knowledge. If you can find a Nexus S that has the North American bands it will do AT&T 3G (it will be the Canadian version). The normal Nexus S state-side is the AWS packed version (AWS = 1700 or T-Mobile 3/4G).
900/2100 are your standard European international 3G spectrum, and well 2100 is pretty much everywhere, even China as you found!
Say you go the AT&T store and ask them for a "World" phone then it is more than likely banded for 2100 in addition to 850/1900!
I hope that helps you!
EDIT: On PDADB.net you will want to look for UMTS850, UMTS1900, UMTS2100. IF it says GSM850, 1900, etc. that means it will do 2G on those bands but not pick up 3G on them!
EDIT 2: Nexus S with AT&T bands can be found here just click on Source 1 at the bottom of the article!

Thanks all! Yes, big help.
Where I live the i9020a hasn't appeared, and why should it? It's needed only in America. Meanwhile, the LG Optimus 2X is the same price here as the Nexus S, which is very very tempting.
Still, I may hold out until the i9020a or the white version of the Nexus S appears, and decide accordingly.

Global roaming with 4G LTE, does it require a SIM card?

Just did some study about 4G LTE, it turns out it is a "natural evolution" for GSM carriers. One important feature of 4G LTE is its inter-operability, ie, global roaming.
I wonder if a special SIM card is needed in order to be able to take advantage of this feature. Can someone step in to share what you know about global roaming in 4G LTE device?
Thanks.

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Thread moved to Q&A due to it being a question. Would advise you to read forum rules and post in correct section.
Failure to comply with forum rules will result in an infraction and/or ban depending on severity of rule break.

[Q] Using US T-Mobile in the UK

Hi I have the G2X from T-Mobile:
GSM: 850, 900, 1800, 1900 MHz
UMTS: 1700/2100, 2100 MHz
will this phone work in the UK on 3G.... will be traveling there shortly and although I believe it should work I have read lots of opposing view points on the web.
Thanks!

Please use the Q&A Forum for questions &
Read the Forum Rules Ref Posting
Moving to Q&A

lufc said:
Please use the Q&A Forum for questions &
Read the Forum Rules Ref Posting
Moving to Q&A
Click to expand...
Click to collapse
wow sorry about that... and believe it or not I'm not a noob!

Bump!

Well I had a UK T-Mobile phone that I used to take with me to the US and it automatticly worked on US T-Mobile...so I guess it would?

Decided to go with an unlocked Samsung Galaxy Nexus. Of course this is Pentaband so I figured it was the safest bet. Works like a dream. For those in Canada, I bought this from Telus and used it on Wind. I'm now in the UK using it at 3G+ speeds on O2. Also just happens to be the best phone that I've ever used!

Verizon 4G LTE/CDMA work in 3G GSM

Dear All,
I have purchased Galaxy Nexus from someone in US (From Amazon) as GSM phone but when I received the phone here in Egypt I founded it Verizon 4G LTE/CDMA
Now What shall I do Is it possible to work here in 3G Network???? this guy cheated me.
Please I need your help.
Regards,

I sympathize with your situation, but cross/double posting is not allowed. Please familiarize yourself with forum rules and do not post the same thing across multiple threads or sections. Thread closed.

[Q] LG D820 Bands - Unlock?

Hello,
because the N5/32GB version for CZ wont be available at least until the next year, I ordered the phone via shipto from US. I thought that google done the homework correctly for the first time and that they will finally have first global device, unfortunately either of us, google end me didn't done the home work correctly.
So now I'm waiting for the US device LG D820 which will work here on the GSM, but its not supporting bands on which the is/will be running in CZ
as following list:
en.wikipedia.org/wiki/List_of_LTE_networks - cant post URLs :crying:
According what i found on the internet:
Networks (North America) - LG D820
GSM: 850/900/1800/1900 MHz
CDMA: Band Class: 0/1/10
WCDMA: Bands: 1/2/4/5/6/8/19
LTE: Bands: 1/2/4/5/17/19/25/26/41
Networks (Rest of World) - LG D821
GSM: 850/900/1800/1900 MHz
WCDMA: Bands: 1/2/4/5/6/8
LTE: Bands: 1/3/5/7/8/20
And according to the band list in CZ LTE is or will be running on bands 3,7 and 20. From what i have read from other posts, forums, pages, fcc and so on it looks like the device or hw on the device should be able to work on all bands but it acts on localized firmware configuration.
My question is there or would somebody working on a fix which will enable all the LTE bands on the phone, from what i understand its just about flashing the right firmware for the chip so if somebody would found the way if there wont be way to make the phone global would be there way at-lest to flash 821 to 820 and vice-versa? I can survive on the 3G for some time but in other hand in the future i want to use the LTE....
Please feel free to copy & paste from this thread as well to cross link this thread with others threads about this topic.

How are you going to enable the lack of physical antenna paths, power amplifiers, and proper RF front end in general for those bands? Two phones are physically different.

milan03 said:
How are you going to enable the lack of physical antenna paths, power amplifiers, and proper RF front end in general for those bands? Two phones are physically different.
Click to expand...
Click to collapse
Well my idea was that the phones ale physically same and that the only difference are the enabled bands. Where did you found the details about the physical differences? Please post...
Edit1 Pardon my ignorance but if we are talking about enabling bands on D820:
Networks (North America) - LG D820
GSM: 850/900/1800/1900 MHz
CDMA: Band Class: 0/1/10
WCDMA: Bands: 1/2/4/5/6/8/19
LTE: Bands: 1/2/4/5/17/19/25/26/41
I see that this phone have more radios/antennas then the EU spec, or you want to tell me that for each LTE band there is a special dedicated antenna, amp and so on?....
This looks kind a strange to me since i found somewhere else that the phones have same HW, somebody was posting on one of the threads bellow that only difference between 821 and 820 was one resistor and that was even between 32gb and 16gb versions otherwise that person was sending that they are literally the same.
Also these days i would expect that they will not completely develop two different devices. My assumptions are that they don't want to sell the full 13 band phone in the US because of the regulations since LTE is disturbing GPS used by US-US military so because of that some bands are dropped in the US and FCC will not approve such devices, but that are just my wild assumptions since i don't live in US.

I can't say for sure whether or not the d820 can be 'unlocked' for more bands or not, but if the d820 and d821 are exactly the same except a software lock on the radios, why would the d821 even exist. Why not just, not lock the radios via software if indeed that is what's happening and boast about having a truly world traveling phone. Again I can't dispute yes or no about the radios existing and being locked or not, just seems illogical if that is the case.
Sent from my Nexus 5 using Tapatalk

corythug said:
I can't say for sure whether or not the d820 can be 'unlocked'
Click to expand...
Click to collapse
I can. Its a hardware limitation. The US are crazy with their bands so they need a dedicated radio just for them
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milan03 said:
How are you going to enable the lack of physical antenna paths, power amplifiers, and proper RF front end in general for those bands? Two phones are physically different.
Click to expand...
Click to collapse
rootSU said:
I can. Its a hardware limitation. The US are crazy with their bands so they need a dedicated radio just for them
-----------------------
Sent via tapatalk.
I do NOT reply to support queries over PM. Please keep support queries to the Q&A section, so that others may benefit
Click to expand...
Click to collapse
Well it would be nice to unlock it but after some more research i found it that for this phone, LTE will be only available here on band 3, one operator is testing this for a year now, another(which i use) started last month, the third we have heave will start next year. So at the end i don't care about this, cos i don't have unlimited data-plan anyway and even the 3G is pretty ****ty here so I don't expect that it will work least in another 12 months and then that the coverage will be good enough. Also since i will save up approx 1/3 of the estimated price what the 32GB device will cost here, I'm pretty much happy

I think need hardware and sofwtare change

dmitrik said:
I think need hardware and software change
Click to expand...
Click to collapse
ROMs between D820 and D821 are compatible with each other. Each Radio Hardware device has it's own Baseband, which is technically software.
A D820 will still work up to DC-HSPA everywhere in the world though. It is only LTE that is missing.